How many bags of concrete are in a cubic yard?

It depends on the bag size. An 80-lb bag yields about 0.6 cubic feet. One cubic yard (27 cubic feet) requires approximately 45 bags of 80-lb concrete.

How thick should a concrete slab be?

Standard residential slabs are 4 inches thick. Driveways and garage floors should be 5-6 inches. Heavy-load areas may require 8+ inches with reinforcement.

How much extra concrete should I order?

Order 5-10% more than calculated to account for uneven ground, form deflection, and spillage. Running short mid-pour creates weak joints in the finished concrete.

Home & DIY

Concrete Calculator

Calculate how much concrete you need in cubic yards, meters, and number of bags.

Processed in your browser

Quick Presets

Unit

Length (ft)

Typical slab: 8-20 ft

Width (ft)

Sidewalk: 3-4 ft, Patio: 8-12 ft

Depth (in)

Standard: 4 in (slab), 6 in (driveway)

Cubic Yards

1.23yd³

Cubic Meters

0.94m³

Cost Comparison

Ready Mix

Bags

Ready Mix: ~$18580 lb Bags: ~$364

Result

80 lb Bags56 bags

60 lb Bags75 bags

Volume33.3 ft³

Practical Tips

●Order 10% extra concrete to account for waste and spillage
●Ready-mix delivery is more economical for orders over 1 cubic yard
●Standard slab thickness is 4 inches; driveways need at least 6 inches
●Concrete cures in 24-48 hours but reaches full strength in 28 days

Recommended ToolRecipe Collection

Allrecipes

Discover thousands of tested recipes, meal plans, and cooking tips.

Try Free

What is Concrete Calculator?

A concrete calculator estimates the volume of concrete needed for a slab, footing, column, or post in cubic yards or bags. Getting the right amount prevents costly waste from over-ordering or project delays from under-ordering.

How to Use

Select the shape of your project (slab, cylinder, footing, steps)
Enter the dimensions: length, width, and depth/thickness
Add a waste percentage (5-10% is typical)
View the total volume in cubic yards and the number of bags needed

Formula

Volume = Length x Width x Depth. Convert to cubic yards by dividing by 27 (since 27 cubic feet = 1 cubic yard)

Frequently Asked Questions

How many bags of concrete are in a cubic yard?: It depends on the bag size. An 80-lb bag yields about 0.6 cubic feet. One cubic yard (27 cubic feet) requires approximately 45 bags of 80-lb concrete.
How thick should a concrete slab be?: Standard residential slabs are 4 inches thick. Driveways and garage floors should be 5-6 inches. Heavy-load areas may require 8+ inches with reinforcement.
How much extra concrete should I order?: Order 5-10% more than calculated to account for uneven ground, form deflection, and spillage. Running short mid-pour creates weak joints in the finished concrete.

View all Home & DIY tools

Related References

Unit Conversion Table